IDENTIFICATION AND CHARACTERIZATION OF THE CELL-SURFACE 70-KILODALTONSIALOGLYCOPROTEIN(S) AS A CANDIDATE RECEPTOR FOR ENCEPHALOMYOCARDITISVIRUS ON HUMAN NUCLEATED CELLS
Ym. Jin et al., IDENTIFICATION AND CHARACTERIZATION OF THE CELL-SURFACE 70-KILODALTONSIALOGLYCOPROTEIN(S) AS A CANDIDATE RECEPTOR FOR ENCEPHALOMYOCARDITISVIRUS ON HUMAN NUCLEATED CELLS, Journal of virology, 68(11), 1994, pp. 7308-7319
The attachment of encephalomyocarditis (EMC) virus to human nucleated
cells susceptible to virus infection was examined with HeLa and K562 c
ell lines. Both cell types showed specific virus binding competitively
blocked by unlabeled virions. The number of binding sites for EMC vir
us on HeLa and K562 cells were approximately 1.6 x 10(5) and 3.5 x 10(
5) per cell, respectively, and dissociation binding constants were 1.1
and 2.7 nM, respectively. Treatment of cells with cycloheximide after
pretreatment with trypsin eliminated EMC virus attachment, suggesting
that the virus-binding moiety is proteinaceous in nature. Digestion o
f cells, cell membranes, and sodium deoxycholate-solubilized cell memb
ranes with proteases or neuraminidases or treatment of cells with lect
ins demonstrated that the EMC virus-cell interaction is mediated by a
sialoglycoprotein. Proteins with a molecular mass of 70 kDa were isola
ted from detergent-solubilized cell membranes of both HeLa and K562 ce
lls by EMC virus affinity chromatography. The purified proteins, as we
ll as their 70-kDa-molecular-mass equivalents detected in intact surfa
ce membranes of HeLa and K562 cells, specifically bound EMC virus in a
virus overlay protein blot assay, whereas membranes from nonpermissiv
e K562 D clone cells did not. Western immunoblot analysis with glycoph
orin A-specific antibody confirmed that the identified 70-kDa binding
site on K562 cells is not glycophorin A, which is the EMC virus recept
or molecule on virus-nonpermissive human erythrocytes (HeLa cells do n
ot express glycophorin A). These results indicate that EMC virus attac
hment to permissive human cells is mediated by a cell surface sialogly
coprotein(s) with a molecular mass of 70 kDa.